Voltage level shifter circuits are commonly implemented using feedback amplifier topologies. Current mirror circuits have been used in various circuit implementations. A current mirror circuit is a current input/output device which, ideally, has zero input impedance and infinite output impedance so that the current output of a mirror circuit remains a fixed function of current input. A general background discussion of conventional mirror circuits is set forth in U.S. Pat. Nos. 5,311,115 and 5,515,010, which are incorporated herein by reference.